Summary of Work: 1) We examined the association between menstrual and reproductive factors and ischemic heart disease in a cohort of 867 white, college educated women who prospectively recorded menstrual cycle data for at least 5 years from their early 20's through their menopause. The analysis included 44,899 person-years and 45 cases of myocardial infarction, angioplasty, heart bypass surgery, or IHD-related mortality, with a median age at occurrence of 65 (range 36-75) years. IHD risk decreased with increasing age at menarche (age-adjusted risk ratio, RR, 0.76 per year, 95% confidence interval, CI, 0.60-0.95). Considering menstrual cycle characteristics ages 28-32, there was no linear association with length, variability, or bleeding duration. IHD risk appeared increased with a later age at first pregnancy (age-adjusted RR 2.49 for ages $ 33 compared to 25-29), first birth (age-adjusted RR 2.90), and age at last birth (age-adjusted RR 3.79 for ages $ 40 compared to 35-39), but there was no association with high parity. 2)We analyzed data from 4 case-control studies pertaining to ovarian cancer risk in relation to pregnancy history: 628 cases and 3432 controls, ages 18-79, were included. An early age at first pregnancy was associated with an increased risk of ovarian cancer (odds ratio 1.38, 95% confidence interval (1.05 - 1.82) for ages # 19 compared to $ 25). Pregnancy recency, as measured by years since last pregnancy, was also associated with increased ovarian cancer risk, with odds ratios of 1.41, 1.43, 1.75, and 2.09 for 10-14, 15-19, 20-24, and $ 25 years compared to 0-9 years (trend test p = 0.004), respectively. These observations support the results from a previous study, and raise additional questions about the role of pregnancy in the etiology of ovarian cancer.